Agriculture
Agricultural monitoring combines soil-level sensors (moisture, pH, leaf wetness) with above-canopy weather and radiation sensing, on a shared RS485/Modbus data bus, to drive irrigation, disease-prevention and growth-model decisions.
What agricultural monitoring needs to measure
Crop and irrigation decisions depend on more than air temperature. Soil moisture, soil pH, soil temperature and leaf wetness directly drive irrigation scheduling and disease risk, while photosynthetically active radiation (PAR) and weather parameters (rainfall, wind, humidity) drive growth-model and spray-timing decisions. A useful agricultural monitoring setup usually combines soil-level sensors with an above-canopy compact weather sensor, on one shared communication bus.
Soil sensors
The ZSTM-3 soil sensor measures moisture (0-100% volumetric content, FDR principle) and electrical conductivity in one probe, used for irrigation scheduling in orchards, vineyards and cash crops. The ZSPH soil pH sensor gives a direct 0-14 pH reading with built-in temperature compensation. The ZLW-2 leaf wetness sensor detects fog, ice, rain and dew on plant canopies dielectrically, feeding disease-prevention and spray-timing decisions. The ZSHF-2 soil heat flux sensor measures the thermopile-based energy balance at the soil surface for agricultural research applications.
Above-canopy weather and radiation
The ZPAR quantum sensor measures photosynthetically active radiation (400-700 nm) with no external power required, the direct input to crop growth models. A compact weather sensor from the ZWS series (typically ZWS400 or ZWS600, depending on whether wind data is needed) provides temperature, humidity, rainfall and optionally wind speed and direction from one housing mounted above the crop canopy.
Why RS485/Modbus matters here
All of these sensors share the RS485/Modbus RTU interface, so a single data logger can poll soil probes and above-canopy sensors together on one bus, rather than requiring separate systems for below-ground and above-ground monitoring.
Installation note
Recommended installation height for a compact weather sensor above a crop canopy is around 3 metres, with a minimum of 1.5 metres above vegetation to avoid interference with the wind and rainfall readings, per the manufacturer's guidance for the ZWS series.
Relevant products
Frequently asked questions
Can soil sensors and a weather sensor share one data logger?+
Yes. Both soil probes and compact weather sensors in this range use RS485/Modbus RTU, so they can share one bus and one data logger with unique Modbus addresses per sensor, rather than needing separate systems above and below ground.
What does the leaf wetness sensor actually detect?+
It detects fog, ice, rain and dew forming on the plant canopy using a dielectric sensing principle, giving 0-100% humidity readings with ±5% accuracy, used to time fungicide spraying and assess disease risk.
Do these sensors need mains power in the field?+
No. Most run on DC 12/24V with solar power compatibility, suited to field locations without mains electricity, and the ZPAR quantum sensor specifically needs no external power at all.